Texture nodes have been implemented by recursively (backwards) calling parent nodes, this gives issues for viewers, previews and threads in general.We will try to keep it stable, but the functionality for this is going to replaced with a better shader system in 2.6. (compositor and material nodes call nodes forward, sorted on dependency. Each node is only called once this way).

Render display in Image window, for a window previously showing UV editor, doesn't restore correctly. (T26828). Code for this is too much spread around and fuzzy, needs full revision.